Method for developing one-component diazotype materials



United States Patent 3,418,120 METHOD FOR DEVELOPING ONE-COMPONENT DIAZOTYPE MATERIALS Bernard 1. Halperin, Glen Aubrey, N.Y., and James 0.

Thompson, Los Gatos, Calif., assignors to International Business Machines Corporation, Armonk, N.Y., a corporation of New York No Drawing. Filed Dec. 28, 1965, Ser. No. 517,082 9 Claims. (Cl. 96-49) The present invention relates to a method for the development of one-component diazotype materials. In a specific embodiment, the invention is concerned with the development of one component diazotype materials in which the light sensitive diazonium salt is contained in a hydrophobic film or layer.

One-component diazotype materials offer a number of advantages over two component systems. The one-component films are free from problems of precoupling and therefore offer the ultimate in shelf life. Such films also can be posted, i.e., localized areas of the film can be exposed and developed without the fogging of adjoining areas. End-use multiplicity or flexibility is also a major feature of one-component diazotype papers and films. For example, by varying the developing agents, i.e., the coupler and alkaline material, the UV density, visible density, color and other characteristics of the film can be controlled to suit specific needs. In particular, the film may be developed with very fast, low molecular weight couplers which are not adaptable to use in two-component systems.

Despite the apparent advantages of one-component diazotype materials, the use of films of this type has been very limited. The only commercially available systems employ aqueous-coupler or aqueous-alkali-coupler developer compositions. In order to make the one-component diazotype films compatible with this mode of development, they are treated to provide them with a hydrophilic surface. The necessity for specially treated hydrophilic diazotype elements, the properties of such films, the need for special apparatus to manipulate an aqueous developer composition whether for papers or films, and other aspects of such a system sharply limit its usefulness.

Therefore, the object of the present invention is to provide a method for rapidly and efiiciently developing onecomponent diazotype materials.

Other objects and advantages of the invention will become apparent in the light of the following detailed description which illustrates a preferred embodiment of the invention and the best mode that has been contemplated for carrying it out.

In general, the present invention comprises developing a one-component diazotype film, paper or other element by applying to the element a vaporized coupler under a controlled pressure of at least about 2 atmospheres and preferably from about 2 to 6 atmospheres. Pressures above 6 atmospheres may be employed but no significant further advantage is gained. An alkaline developing agent is preferably incorporated in the vaporized coupler. In addition, a nonreacting, volatile solvent may be included in the coupler-alkali solution to assist in the formation of the developing vapor. In an alternative embodiment, the diazotype material may first be contacted with the vaporized coupler under pressure and then with the alkaline developer.

In a preferred procedure, a diazo coupler is dissolved in an alkaline developing agent. The developing agent may be a volatile base, such as anhydrous ammonia, methylamine, an imine, etc. Most common diazo couplers are soluble in one or more of such bases, as for example, acetoacetanilide, 2,3 dihydroxynaphthalene 6 sulfonic acid, 3-methyl-1-phenyl-2-pyrazoline-5-one, and 2,4-resorcylic acid. It should be recognized that each of these conplers is representative of a separate class of diazo coupling compounds which encompasses a large number of compounds having similar solubility characteristics. Where a secondary, non-reactive solvent is employed, any suitable compound, such as one of the well known Freon propellant gases may be utilized.

Where extremely fast and active couplers are used, the application of an alkaline developing agent may be unnecessary, since in many instances the coupling reaction proceeds rapidly in the absence of a base.

The coupler, alkaline developer and, if desired, a secondary solvent are mixed to form a solution. The resulting solution is then vaporized. As used in the present context, the term vapor is meant to imply not only a true vapor, but also any atomized or nebulized cloud, aerosol, mist or the like having similar characteristics.

The vaporized solution is then contacted with a one component diazotype film, paper or like element in a suitable developing chamber which permits control of the pressure of the vapors at a level in the range of from about 2 to 6 atmospheres or higher. The developing chamber conveniently may be provided with means for preliminarily purging or evacuating the atmosphere within the chamber prior to development and for removing residual vapors after development.

In an alternative embodiment, the coupler alone is first vaporized, preferably by being converted to an atomized or aerosol form, and is then applied to the diazotype material under a pressure of from 2 to 6 atmospheres or higher. The alkaline developer is then separately applied to develop the image.

The present invention is applicable to conventional onecomponent elements currently in use with aqueous alkalicoupler developers. Such materials generally comprise a support or substrate which may be paper, in tissue, cardstock or sheet form, a transparent film, a glass plate or other material. The base or substrate is impregnated with or provided with a surface layer or film comprising a light sensitive diazonium compound distributed in a hydrophilic, film-forming carrier.

More important, however, is the fact that the present technique permits the rapid and efficient development of one-component diazotype materials provided with hydrophobic surfaces. The use of hydrophobic films and layers provides dimensionally stable elements having good shelf life. Such materials may, for example, be made hydrophobic by coating them with sizing solutions of water insoluble resins or polymers. It is theorized that the vaporized coupler, applied under pressure, has a mobility and activity that enables it to penetrate even a hydrophobic surface for rapid development of the contained diazonium compound.

The following detailed examples will assist toward a better understanding and appreciation of the invention.

EXAMPLE 1 A sheet of paper is coated with a stabilized aqueous solution of 2,S-diethoxy-p-morpholinobenzene diazonium chlorozincate and is dried to provide a one-component diazotype paper.

A coupler solution is prepared by dissolving 10 g. of acetoacetanilide in cc. of methyl ethyl ketone.

The diazotype paper is selectively exposed and is placed in a developing chamber having a volume of about 10 cc. The chamber is of cylindrical form and is provided with a close fitting plunger.

The coupler solution is vaporized in a De Vilbiss ultrasonic nebulizer of the type described above. After the developing chamber is purged, vapors of the coupler solution are introduced and the plunger is depressed for about one second or less to place the vapors in contact with the diazotype paper under a pressure of about 2 atmospheres.

The coupler vapors are then exhausted from the chamber and the paper is contacted with ammonia vapors to complete the development. A red dye image is produced.

EXAMPLE 2 The procedure of Example 1 was followed, but the vaporized coupler solution was mixed with air, as a neutral carrier gas.

EXAMPLE 3 The procedure of Example 1 was followed but 1 cc. of triethylamine was incorporated in the coupler solution prior to vaporization. The vapors were mixed with Freon, as a neutral carrier gas, and then contacted with the diazotype paper. Further development is unnecessary.

EXAMPLE 4 A coupler solution was prepared by dissolving 10 g. of acetoacetanilide in 1 cc. of liquid ammonia. The vapors from a tank of this solution were then contacted with an exposed diazotype paper as described in Example 1 under a pressure of 2 atmospheres. This completes development of the image. Vapors from a tank of such a solution are under sufiicient pressure and contain sufiicient coupler to develop diazotype images eifectively.

EXAMPLE 5 The procedure of Example 5 was followed, but 1 cc. of triethylamine was mixed with the coupler solution prior to vaporization. The vapors were mixed with air as an inert carrier gas, prior to contact with the film. Due to the presence of the triethylamine base in the vapors, further development, as in Example 1, is unnecessary.

EXAMPLE 7 A film sample prepared as in Example 5 is developed as in Example 4, but 3-methyl-1-phenyl-2-pyrazoline-5-one is substituted for the acetoacetanilide.

EXAMPLE 8 A glass substrate is coated with a solution of 2,5-diethoxy-p-morpholinobenzene diazonium fluoborate containing a vinyl acetatevinyl chloride copolvmer. The copolymer is a hydrophobic, film forming carrier and also serves to promote adhesion of the composition to the glass. The resulting film is dried to provide a one-component diazotype plate.

A coupler solution is prepared by dissolving 10 g. of 2,4 resorcyclic acetamide in 100 cc. of methyl ethyl ketone. The solution is then vaporized and the plate contacted with the vapors as in Example 1. Development is completed as in Example 1, yielding a purple-blue dye image.

EXAMPLE 9 A glass supported diazotype element as prepared in Example 8 is developed with a vaporized coupler solution as described in that example, but also containing 1 cc. of triethylamine.

EXAMPLE 10 A glass supported diazotype element as prepared in Example 8 was developed according to the procedure of Example 4, but 2,4-resorcyclic acetamide was substituted for the acetoacetanilide in the liquid ammonia solution.

It will be obvious to those skilled in the art that various changes may be made in the compositions and procedures described herein without departing from the spirit and scope of the invention as expressed in the following claims.

What is claimed is:

1. A method for developing a one-component diazotype element comprising,

vaporizing a diazo coupler, and

contacting said element with said coupler at a pressure of at least about 2 atmospheres.

2. The method of claim 1 further comprising contacting said element with an alkaline developing agent.

3. The method of claim 1 wherein said element comprises a substrate coated with a light sensitive diazonium salt distributed in a hydrophobic, film-forming carrier.

4. The method of claim 1 wherein said element comprises a substrate coated with a light sensitive diazonium salt distributed in a hydrophilic, film-forming carrier.

5. A method for developing a one-component diazotype element comprising,

dissolving a diazo coupler in a volatilizable base to form a developer solution,

vaporizing said solution, and

contacting said element with said solution at a pressure of at least about 2 atmospheres.

6. The method of claim 5 wherein said element comprises a substrate coated with a light sensitive dazonium salt distributed in a hydrophobic, film-forming carrier.

7. The method of claim 5 wherein said element comprises a substrate coated with a light sensitive diazonium salt distributed in a hydrophilic, film-forming carrier.

8. The method of claim 5 further comprising incorporating in said solution a secondary, nonreactive solvent for said coupler.

9. The method of claim 5 wherein said solution is vaporized by means of ultrasonic vibration.

References Cited UNITED STATES PATENTS 2,789,904 4/1957 Benbrook et al. 96-91 XR FOREIGN PATENTS 727,676 4/ 1955 Great Britain. 815,005 6/ 1959 Great Britain. 1,321,669 2/ 1963 France.

OTHER REFERENCES Anon: West Reproduction, Dearborn, Mich., 4 pages, November 1960'.

NORMAN G. TORCHIN, Primary Examiner.

C. BOWERS, Assistant Examiner. 

1. A METHOD FOR DEVELOPING A ONE-COMPONENT DIAZOTYPE ELEMENT COMPRISING, VAPORIZING A DIAZO COUPLER, AND CONTACTING SAID ELEMENT WITH SAID COUPLER AT A PRESSURE OF AT LEAST ABOUT 2 ATMOSPHERES. 